Some aircraft systems, such as environmental control systems (ECS) and wing de-icing systems for instance, require pressurized air from the engine within pre-established pressure and/or temperature specifications. In the case of ECS, for instance, it was known to use pressurized air from a compressor stage of the gas turbine engine via a bleed air conduit, and to cool this pressurized air in a dedicated heat exchanger, referred to as the ECS pre-cooler, provided as part of the aircraft.
Engine systems, such as bearing cavities for the rotary components of gas turbine engines, also require pressurized air (referred to as buffer air) within pre-established pressure and/or temperature specifications. The engine systems requirements can significantly differ from the pressure and/or temperature specification of aircraft systems. The engine (buffer) air cooling system thus used a dedicated heat exchanger provided as part of the gas turbine engine.
There remained room for improvement in the way the cooling of engine air and/or aircraft air was handled.